The Brain
Is a very complex organ- one of the largest in the body in fact, weighing about 2kg! In adults it consumes around 20% of the energy that we intake (through food) and it is most definitely affected by what we eat and drink, but also by environmental impacts (eg lead poisoning) and drugs.
Our brains are made up of one hundred billion neurones Each one has branch-like projections at its end called dendrites, which form connections with other neurones across junction points called synapses.
The brain is rich in lipids (fats) which is one reason why it is essential to maintain healthy fats in the diet. Some other very important nutrients are iodine which is needed for making thyroid hormones which are involved in brain development, folic acid (essential in a developing foetus’ brain), iron and omega 3 fatty acids (for brain cell membranes). Zinc, magnesium, selenium, the B vitamins , vitamins C, and E…all play a part in maintaining healthy brain function.
As well as cognitive decline (Alzheimers, dementia, reduced memory…) a diet lacking the range of nutrients necessary for brain health seems to increase risk of depression, ADHD, and schizophrenia.
Pathology of Alzheimers
Dementia is the leading cause of disability in Australians aged 65 years and over. In Australia in 2011 62% of dementia sufferers were women.
Early symptoms are memory loss, confusion, personality changes, apathy and withdrawal.
There are several causes of dementia- Alzheimers disease is common, but Parkinson’s and Huntingdon’s Disease can also cause dementia.
Alzheimers occurs due to an accumulation of amyloid plaques and neurofibrillary tangles in the brain, due to abnormal protein processing. There is some synaptic loss and loss of connectivity between synapses in specific parts of the brain right from the start, seemingly from degeneration of neuronal membranes.
In Alzheimers some hundreds of thousands of synaptic connections and neurones are lost DAILY. It is crucial to target these losses early in disease progression. The aim is not only to slow or stop loss, but also to promote the growth of new neurones and make new synaptic connections.
‘Brain Foods’
Iodine deficiency is the leading cause of mental retardation and avoidable brain damage worldwide. Iodine is mainly found in seafood and seaweed, or plants grown in iodine-rich soils. Unfortunately Australian soils are iodine-depleted. As a result, by law, bread in Australia has iodised salt added to it (unless its organic) to address the problem of possible low iodine across the population. Of course this does not benefit people who avoid bread, or eat organic bread. Additionally, iodine is so important during pregnancy for the foetus’ developing brain, but the amount found in fortified bread is insufficient for an expectant mum’s needs.
Omega 3 Fatty Acids such as DHA are found in the neural cell membranes. A derivative of DHA also promotes synapse formation. The richest source of omega 3’s is fish. Pregnant women are advised to limit their intake of fish to two servings per week due to concerns about mercury contamination. This can largely be sidestepped by eating smaller fish (eg sardines, pilchards). According to a WHO/FAO report (2010) the benefits of DHA intake outweigh the risk of mercury ingestion.
Iron is another common deficiency. Iron is needed for various brain related functions including neurological development and functioning.
Souvenaid
A couple of nutritional drinks have been developed to target early stage Alzheimers.(2) One of these, Souvenaid, is available in Australia. It is a cocktail of nutrients known to be good for cognition and has been seen to improve verbal memory in about half of people who take it regularly. Importantly, it is an easy (small milkshake type drink) way to ensure intake of vital nutrients for anyone who might be lacking appetite or lacking cooking skills or knowledge of nutrition (such as some older people). Vitamin D, the fatty acid DHA and lutein and alpha-lipoic acid were studied as possibly beneficial and have been effective in improving memory in animal studies. Vitamin D is another nutrient which may easily become deficient in older people who venture outdoors less often.
Interestingly, none of the supplements developed so far have been as effective as exercise in keeping the memory working well.
What exactly should I be eating to reduce my chances of mental decline?
Well, it should be no surprise that a Mediteranean diet contains many elements which are great for your brain- fish, beans, vegetables, olive oil… but if you really want to target this area of health then you need to get more specific: The MIND diet study was carried out by researchers at Rush University in Chicago after questioning 900 people aged 58-98 years about their usual diet, and carrying out repeated neurological testing.(2) Those that adhered most closely to the MIND recommended diet had a mental “age” 7.5 years younger than those who did not. Even people who only followed the diet moderately well had about a 30% greater chance of avoiding Alzheimers disease.
The MIND diet (1) identifies 10 foods which are great for brain health and 5 to avoid. Watch this video to find out which ones!
It cannot be ignored that genetic factors, smoking and education have an effect on memory. Nevertheless, the MIND diet showed that cognitive decline could be slowed and Alzheimers risk reduced regardless of the presence of other risk factors.
Take Home Message
The MIND diet certainly seems worthwhile for maintaining mental health, especially as it concurs with several other eating patterns which are known to reduce the risk of many other chronic diseases. Although you may be genetically prone to Alzheimers, a healthy diet and, very importantly, exercise and social interaction can reduce that risk substantially.
References
Efficacy of Souvenaid in mild Alzheimer's disease: results from a randomized, controlled trial. Scheltens P1, Twisk JW, Blesa R, Scarpini E, von Arnim CA, Bongers A, Harrison J, Swinkels SH, Stam CJ, de Waal H, Wurtman RJ, Wieggers RL, Vellas B, Kamphuis PJ. J Alzheimers Dis. 2012;31(1):225-36. doi: 10.3233/JAD-2012-121189.
MIND diet associated with reduced incidence of Alzheimer's disease. Morris MC1, Tangney CC2, Wang Y3, Sacks FM4, Bennett DA5, Aggarwal NT5. Alzheimers Dement. 2015 Sep;11(9):1007-14. doi: 10.1016/j.jalz.2014.11.009. Epub 2015 Feb 11